Camera having lens barrier

ABSTRACT

A camera includes a lens support frame which supports a photographing lens group; an outer lens barrel which is provided on the front end thereof with a photographing aperture through which the lens support frame is moved; a lens barrier mechanism which opens and closes the photographing aperture of the outer lens barrel; a lens drive mechanism which moves the lens support frame in the outer lens barrel between a forward movement extremity in which the front end of the lens support frame is located in front of the photographing opening in an optical axis direction, and a rearward movement extremity in which the front end of the lens support frame is located behind the photographing aperture; and a barrier detection device for detecting the opening state of the lens barrier mechanism, based on an amount of movement of the lens support frame in the optical axis direction via the lens drive mechanism.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a camera having a lens barrier.

[0003] 2. Description of the Related Art

[0004] In a known compact camera, etc., a front portion of a lens isautomatically closed by a lens barrier to protect the lens when thecamera is not used. However, in a camera in which a photographingoptical system is independent from an object viewing optical system,even if, upon photographing, the barrier is not completely opened due tosome reason, there is a chance that a photographer (operator) takes apicture without noticing the incomplete opening of the lens barrier,because the incomplete opening of the lens barrier has no influence onan object image viewed by the photographer through the viewing opticalsystem.

SUMMARY OF THE INVENTION

[0005] The present invention provides an inexpensive compact camera inwhich the opening state of the lens barrier can be certainly detected.

[0006] For example, a camera is provided, including a lens support framewhich supports a photographing lens group; an outer lens barrel which isprovided on the front end thereof with a photographing aperture throughwhich the lens support frame is moved; a lens barrier mechanism whichopens and closes the photographing aperture of the outer lens barrel; alens drive mechanism which moves the lens support frame in the outerlens barrel between a forward movement extremity in which the front endof the lens support frame is located in front of the photographingopening in an optical axis direction, and a rearward movement extremityin which the front end of the lens support frame is located behind thephotographing aperture; and a barrier detection device for detecting theopening state of the lens barrier mechanism, based on an mount ofmovement of the lens support frame in the optical axis direction via thelens drive mechanism.

[0007] The barrier detection device can detect the opening state of thelens barrier mechanism based on an amount of forward movement of thelens support frame from the rearward movement extremity.

[0008] The photographing lens group can include a focusing lens group.The lens drive mechanism includes a focus drive mechanism which movesthe lens support frame to an in-focus position of the focusing lensgroup, based on an object distance; and the barrier detection devicecauses the focus drive mechanism to move the lens support frame,independently of a focusing operation, to detect the opening state ofthe lens barrier, based on the amount of movement of the lens supportframe.

[0009] The photographing lens group can include front and rear sub-lensgroups. The lens support frame can include front and rear lens supportframes which support the front and rear sub-lens groups, respectively.The lens drive mechanism can be a sub-lens group shifting device whichmoves the front lens support frame between a mutually close position inwhich the front lens support frame is close to the rear lens supportframe, and a mutually distant position in which the front lens supportframe is distant from the rear lens support frame. The front lenssupport frame can be supported in the mutually close position when thecamera is not used, and the front lens support frame is moved from themutually close position to the mutually distant position by the sub-lensgroup shifting device when the camera is used, so that the barrierdetection device detects the opening state of the lens barrier based onthe amount of movement of the front lens support frame.

[0010] The camera can include a zoom lens camera, and the sub-lens groupshifting device can move the front lens support frame between themutually close position and the mutually distant position with respectto the rear lens support frame, in accordance with the movement of thezoom lens between a telephoto side photographing position and awide-angle side photographing position.

[0011] The camera can further include a focus drive mechanism whichmoves the front lens support frame together with the rear lens supportframe to an in-focus position in the optical axis direction, inaccordance with an object distance. The barrier detection device causesthe focus drive mechanism to integrally move the front and rear lenssupport frames together in the optical axis direction, independently ofa focusing operation, to detect the opening state of the lens barrier inaccordance with the amount of movement of the front end rear lenssupport frames.

[0012] The camera can further include an indication device forindicating interference of the lens support frame with the lens barrier,detected by the barrier opening state detection device.

[0013] The camera can further include a control device for prohibiting aphotographing operation when interference of the lens support frame withthe lens barrier is detected by the barrier detection device.

[0014] The present disclosure relates to subject matter contained inJapanese Patent Application No. 2001-81610 (filed on Mar. 21, 2001)which is expressly incorporated herein by reference in its entirety.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The invention will be discussed below with reference to theaccompanying drawings, in which:

[0016]FIG. 1 is an exploded perspective view of components of a zoomlens barrel, according to the present invention;

[0017]FIG. 2 is a sectional view of an upper half of the zoom lensbarrel in a retracted position;

[0018]FIG. 3 is a sectional view of an upper half of the zoom lensbarrel in a wide-angle position;

[0019]FIG. 4 is a sectional view of an upper half of the zoom lensbarrel in a telephoto position;

[0020]FIG. 5 is a perspective view of the zoom lens barrel in anadvanced position;

[0021]FIG. 6 is an exploded perspective view of the zoom lens barrelshown in FIG. 5;

[0022]FIG. 7 is an exploded perspective view of the zoom lens barrel,showing a more detailed disassembly than FIG. 6;

[0023]FIG. 8 is a perspective view of first and second outer barrels;

[0024]FIG. 9 is a perspective view of a third linear guide ring;

[0025]FIG. 10 is an exploded perspective view of a third linear guidering and a lens-shutter unit;

[0026]FIG. 11 is a developed view of a third linear guide ring, showinga diaphragm control cam groove thereof;

[0027]FIG. 12 is a developed view of an inner surface of a cam ring,showing a cam groove profile, by way of example;

[0028]FIG. 13 is an exploded perspective view of a lens-shutter unit;

[0029]FIG. 14 is an exploded perspective view of a rear unit of alens-shutter unit;

[0030]FIG. 15 is a sectional view of an upper half of a rear unit of alens-shutter unit;

[0031]FIG. 16 is a perspective view of a front unit of a lens-shutterunit and a lens-shutter unit FPC (annular FPC);

[0032]FIG. 17 is an exploded perspective view of a front holder ring andan annular FPC;

[0033]FIG. 18 is an exploded rear perspective view of a front unit and arear unit, of a lens-shutter unit;

[0034]FIG. 19 is a rear perspective view of an assembly of a front andrear unit, of a lens-shutter unit;

[0035]FIG. 20 is an exploded perspective view of a first variable powerlens group and surrounding components thereof;

[0036]FIG. 21 is an exploded perspective view of a lens-shutter unit anda lens support barrel;

[0037]FIG. 22 is an enlarged developed view of a front sub-lens groupframe, a rear sub-lens group frame and a drive ring, in connection witha front hold ring;

[0038]FIG. 23 is an explanatory view showing a focusing operation usinga drive ring;

[0039]FIG. 24 is an enlarged sectional view of an upper half of alens-shutter unit and the surrounding components thereof when a lensbarrier thereof is closed;

[0040]FIG. 25 is a sectional view similar to FIG. 24, when a lensbarrier is open;

[0041]FIG. 26 is a block diagram of a control system of a zoom lensbarrel shown in FIGS. 2 through 4;

[0042]FIG. 27 is a flow chart showing the control of detection of theopening and closing of the lens barrier.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0043] The following embodiments are addressed to a zoom lens camerahaving a lens barrier. The structure of the zoom lens barrel in a zoomlens camera will be discussed first and the features of the presentinvention including a lens barrier mechanism will be discussedthereafter.

[0044] As shown in FIG. 1, a stationary barrel 12 secured to a camerabody 11 is provided on its inner peripheral surface with a femalehelicoid 12 a which is screw-engaged with a male helicoid 14 a formed onan outer peripheral surface of a first helicoid ring 14. A pinion 16which is rotated by a zooming motor 15 is provided outside thestationary barrel 12. The pinion 16 is in mesh with a gear 14 b formedon the outer peripheral surface of the first helicoid ring 14 via acut-out portion of the male helicoid 14 a. The gear 14 b is inclined inthe same direction as the lead of the male helicoid 14 a. The firsthelicoid ring 14 is connected at the front end thereof to a first outerbarrel 17. Consequently, when the first helicoid ring 14 is rotated inthe forward or reverse direction by the zooming motor 15, the firsthelicoid ring 14 and the first outer barrel 17, integrally connectedthereto, are moved in the optical axis direction in accordance with theengagement of the female helicoid 12 and the male helicoid 14 a.

[0045] A first linear guide ring 18 which is rotatable relative to, andmovable together with, the first outer barrel 17 in the optical axisdirection (i.e., not relatively movable with respect to the first outerbarrel 17 in the optical axis direction) is supported in the innerperiphery of the first outer barrel 17. The first linear guide ring 18has a projection 18 a which is engaged in a linear guide groove 12 b ofthe stationary barrel 12, so that the first linear guide ring 18 islinearly movable only in the optical axis direction. The axialdisplacement of the first linear guide ring 18 is detected by a brush 19and a code plate 20 secured to the first linear guide ring 18 and thestationary barrel 12, respectively.

[0046] The first linear guide ring 18 is provided on the innerperipheral surface thereof with a female helicoid 18 b which is engagedwith a male helicoid 21 a formed on an outer peripheral surface of asecond helicoid ring 21. The second helicoid ring 21 is provided on theouter peripheral surface thereof with a pair of guide portions 21 bwhich are engaged in guide grooves 17 a (see FIG. 8) formed in the innerperipheral surface of the first outer barrel 17 through guidethrough-grooves 18 c formed in the first linear guide ring 18. The guidethrough-grooves 18 c are elongated through-holes inclined in the samedirection as the female helicoid 18 b, and the guide grooves 17 a arelinear grooves parallel with the optical axis O of the zoom lens system.The second helicoid ring 21 is connected at the front end thereof to asecond outer barrel 23. Consequently, when the first outer barrel 17 isrotated in the forward or reverse direction by the zooming motor 15, thesecond helicoid ring 21 and the second outer barrel 23, integrallyconnected thereto, are rotated in accordance with the engagement betweenthe guide portion grooves 17 a and the guide portions 21 b, andaccordingly, are moved in the optical axis direction with respect to thefirst linear guide ring 18 (and an assembly of the first outer barrel 17and the first helicoid ring 14) in accordance with the female helicoid18 b and the male helicoid 21 a.

[0047] A second linear guide ring 25 which is rotatable relative to, andis movable in the optical axis direction together with, the second outerbarrel 23 (i.e., not movable in the optical axis direction relative tothe second outer barrel 23) is supported in the second outer barrel 23.The second linear guide ring 25 has a projection 25 a which is engagedin a linear guide groove 18 d of the first linear guide ring 18, so thatthe second linear guide ring 25 is linearly movable only in the opticalaxis direction.

[0048] Similar to the first linear guide ring 18, the second linearguide ring 25 is provided on the inner peripheral surface thereof with afemale helicoid 25 b which is engaged with a male helicoid 30 a formedon an outer peripheral surface of a rear end of a cam ring (third outerbarrel) 30. The cam ring 30 is provided on the outer peripheral surfacethereof with a pair of guide portions 30 b which are engaged in guidegrooves 23 a (see FIG. 8) formed in the inner peripheral surface of thesecond outer barrel 23 through guide through-grooves 25 c formed in thesecond linear guide ring 25. The guide through-grooves 25 c are in theform of elongated through-holes inclined in the same direction as thefemale helicoid 25 b, and the guide grooves 23 a are in the form oflinear grooves parallel with the optical axis O. Consequently, when thesecond outer barrel 23 is rotated in the forward or reverse direction bythe zooming motor 15, the cam ring 30 is moved in the optical axisdirection relative to the second linear guide ring 25 (and an assemblyof the second outer barrel 23 and the second helicoid ring 21), inaccordance with the engagement between the female helicoid 25 b and themale helicoid 30 a.

[0049] A third linear guide ring 33 which is rotatable relative to, andis movable in, the optical axis direction together with the cam ring 30(i.e., not movable in the optical axis direction relative to the camring 30) is supported in the cam ring 30. The third linear guide ring 33is provided on the outer peripheral surface thereof with a plurality oflinear guide projections 33 a which are engaged in a linear guide groove25 d formed on the inner peripheral surface of the second linear guidering 25, so that the third linear guide ring 33 is linearly movable onlyin the optical axis direction.

[0050] A lens support barrel (fourth outer barrel) 31 having a firstvariable power lens group L1 (first sub-lens group S1 and a secondsub-lens group S2) and a second lens group frame 32 having a secondvariable power lens group L2 secured thereto are arranged in the camring 30. The lens support barrel 31 and the second lens group frame 32are guided to linearly move in the optical axis direction with the thirdlinear guide ring 33. Specifically, as shown in FIGS. 9 and 10, threearms 33 b, which are provided on the periphery of an imaginary cylinderand constitute the third linear guide ring 33, are each provided on theouter and inner surfaces (front and rear sides) thereof with linearguide grooves 33 c and 33 d which extend parallel with the optical axisO. Linear guide projections (not shown) provided on the inner peripheralsurface of the lens support barrel 31 are movably fitted in therespective linear guide grooves 33 c, and linear guide projections 32 aprovided on the outer peripheral surface of the second lens group frame32 are movably fitted in the respective linear guide grooves 33 d.

[0051] The cam ring 30 is provided on the inner peripheral surfacethereof with bottomed cam grooves 35 and bottomed cam grooves 36 for thelens support barrel 31 and the second lens group frame 32, respectively.FIG. 12 shows a developed view of the bottomed cam grooves 35 and 36.There are three sets of bottomed cam grooves 35 and 36, respectively,and are spaced in the circumferential direction at equal pitches. Thelens support barrel 31 and the second lens group frame 32 are providedwith radially extending cam follower projections 31 a and 32 b which arefitted in the bottomed cam grooves 35 and 36, respectively.

[0052] In FIG. 12, the bottomed cam grooves 35 and 36 have a range ofusage between a telephoto extremity position and a retracted position.Upon photographing, the follower projections 31 a and 32 b are guidedbetween the telephoto extremity position and a wide-angle extremityposition within the range of usage of the bottomed cam grooves 35 and36. The bottomed cam grooves 36 are each provided with an intermediateinterruption portion 36 a between the telephoto extremity and thewide-angle extremity. The first variable power lens group L1 held in thelens support barrel 31 which is guided by the bottomed cam grooves 35has a switching function to move the first sub-lens group S1 and thesecond sub-lens group S2 to a mutually close position and a mutuallydistant position at an intermediate position between the telephotoextremity and the wide-angle extremity. Upon switching of the firstvariable power lens group L1, the second variable power lens group L2passes through the intermediate interruption portions 36 a of thebottomed cam grooves 36. The intermediate interruption portions 36 a arenot used as zooming areas during an actual zooming operation (i.e., thecam ring 30 is not stopped thereat).

[0053] In the zoom lens barrel constructed as above, when the pinion 16is rotated in the forward or reverse direction by the zooming motor 15,the cam ring 30 is moved in the optical axis direction while rotating,so that the lens support barrel 31 (first variable power lens group L1)and the second lens group frame 32 (second variable power lens groupL2), guided in the cam ring 30 to linearly move in the optical axisdirection, are linearly moved in the optical axis direction inaccordance with predetermined profiles of the bottomed cam grooves 35and 36. For instance, in the retracted position of the lens barrel(accommodated position) shown in FIG. 2, the entire zoom lens barrel issubstantially retracted in the camera body. When the zooming motor 15 isdriven in the barrel advancing direction, the zoom lens barrel is movedto the wide-angle extremity position shown in FIG. 3. The zoom lensbarrel can be moved to the telephoto extremity position shown in FIG. 4by further rotation of the zooming motor 15 in the barrel advancingdirection. If the zooming motor 15 is rotated in the reverse direction,the zoom lens barrel is moved from the telephoto extremity position tothe wide-angle extremity position and to the retracted position. Thezooming operation is, in practice, controlled stepwise so that the focallength from the wide-angle extremity and the telephoto extremity issplit into a plurality of focal length steps, wherein the zooming motor15 is stopped at each focal length step to carry out focusing or anexposure. In the control therefor, the area corresponding to theswitching of the first sub-lens group S1 and the second sub-lens groupS2 between the mutually close position to the mutually distant positionis not used for photographing and, hence, the focal length step does notexist in this area, wherein the cam ring 30 (zooming motor 15) does notstop thereat.

[0054] A lens-shutter unit 40 is provided in the lens support barrel 31.As shown in FIGS. 13 and 18, the lens-shutter unit 40 includes a frontsupport ring 41, a rear support ring 42, a gear retainer ring 43 and asector retainer ring 44. The lens-shutter unit 40 can be split into twounits, i.e., a front unit 40A having an assembly including the frontsupport ring 41 and the gear retainer ring 43, and a rear unit 40Bhaving an assembly including the rear support ring 42 and the sectorretainer ring 44.

[0055] The front unit 40A will be discussed below. The front supportring 41 has a center opening 41 a in which the front sub-lens groupframe 45 and the rear sub-lens group frame 46 are fitted. The firstsub-lens group S1 is secured to the front sub-lens group frame 45 andthe second sub-lens group S2 is secured to the rear sub-lens group frame46. The relative axial position of the front sub-lens group frame 45 andthe rear sub-lens group frame 46 (the first sub-lens group S1 and thesecond sub-lens group S2) between the telephoto extremity and thewide-angle extremity can be selectively moved to the mutually distantposition for a short focal length and the mutually close position for along focal length. The relative movement of the axial position of thefront sub-lens group frame 45 and the rear sub-lens group frame 46, andthe focusing operation in which the front sub-lens group frame 45 andthe rear sub-lens group frame 46 are moved together in the optical axisdirection, can be performed by the drive ring 47.

[0056] The rearward extremity of the drive ring 47 is restricted by thereceiving surface 42 s of the rear support ring 42 and is rotatablysupported between the front support ring 41 and the rear support ring42.

[0057] The front sub-lens group frame 45 is cylindrical and is providedon the outer periphery thereof with diametrically opposed linear guideribs 45 a, as shown in FIG. 20. The linear guide ribs 45 a are providedwith guide holes 45 b in which linear guide rods 48 are loosely fitted(inserted). The linear guide rods 48 are secured at the rear endsthereof to securing holes 43 a formed in the bottom of the gear retainerring 43, and the front ends of the linear guide rods 48 are secured to asecuring bracket 49. The securing bracket 49 is secured to the frontsurface of the gear retainer ring 43 with securing screws 50.Compression coil springs 51 which are provided between the securingbracket 49 and the linear guide ribs 45 a surround the linear guide rods48 to bias the front sub-lens group frame 45 toward the rear sub-lensgroup frame 46. The gear retainer ring 43 is provided with generallyU-shaped recesses 43 b in which the linear guide rods 48 and thecompression coil springs 51 are received. The recesses 43 b arecommunicatively connected to the center opening 41 a of the frontsupport ring 41.

[0058] The front sub-lens group frame 45 has four shift leading surfaces(shift cam surfaces) 45 c, which are formed circumferentially atequi-angular intervals on the end-face of the front sub-lens group frame45, in order to move the front and rear sub-lens group frames to amutually close position or a mutually distant position, in the opticalaxis direction. The shift leading surfaces 45 c are provided at theiropposed ends with follower engaging recesses 45 d and 45 e (FIG. 22).Note that only one shift leading surface 45 c is shown in FIG. 22. Therear sub-lens group frame 46 is provided with four follower projections46 a corresponding to the shift leading surfaces 45 c of the frontsub-lens group frame 45. As shown in FIG. 20, the follower projections46 a are provided on the front end portions of inclined surfaces 46 b,corresponding to the shift leading surfaces 45 c of the front sub-lensgroup frame 45. The shift leading surfaces 45 c formed on the frontsub-lens group frame 45 and the follower projections 46 a formed on therear sub-lens group frame 46 constitute a shift cam mechanism for movingthe front sub-lens group frame 45 and the rear sub-lens group frame 46to a mutually close position or to a mutually distant position, in theoptical axis direction.

[0059] The rear sub-lens group frame 46 is also provided with a pair oflinear guide projections 46 c which are located at the samecircumferential positions as two of the four follower projections 46 athat are diametrically opposed, and are provided behind the two followerprojections 46 a in the axial direction. Furthermore, three drivenprojections 46 d are provided on the outer peripheral surface of therear sub-lens group frame 46 and are spaced at equi-angular intervals inthe circumferential direction and behind the linear guide projections 46c in the axial direction.

[0060] The front support ring 41 is provided on the inner peripheralsurface thereof with a pair of rotation preventing surfaces 41 b and 41c (see FIG. 22) which correspond to the linear guide projections 46 c ofthe rear sub-lens group frame 46 and restrict the angular displacementof the rear sub-lens group frame 46 with respect to the front supportring 41, which does not rotate. Namely, the rotation preventing surfaces41 b and 41 c engage with the linear guide projections 46 c to preventfurther rotation of the rear sub-lens group frame 46 at the rotationalmovement extremities thereof when the rear sub-lens group frame 46 isrotated in the forward and reverse directions. Moreover, the rotationpreventing surface 41 b and the guide surface 41 d opposed theretoconstitute a wide-angle linear guide groove 41 e, and the rotationpreventing surface 41 c and the guide surface 41 f opposed theretoconstitute a telephoto linear guide groove 41 g. The linear guideprojections 46 c are substantially snugly engaged in the guide grooves41 e and 41 g at the wide-angle and telephoto extremities, respectively.

[0061] The drive ring 47 has three control recesses 47 a (FIGS. 18 and22) at the front end surface thereof, corresponding to the three drivenprojections 46 d of the rear sub-lens group frame 46. Note that only oneor two control recesses 47 a are shown in the drawings. As shown in FIG.23, the control recesses 47 a are symmetrical in the lateral directionwith respect to a center line ‘c’ parallel with the optical axis, andeach include a pair of effective surfaces 47 b and 47 c which engagewith the driven projection 46 d, and telephoto and wide-angle focusleading surfaces (focus cam surfaces) 47 d and 47 e which abut againstthe arc end-surface of the driven projection 46 d. The telephoto focusleading surface 47 d and the wide-angle focus leading surface 47 e aredefined by end cam surfaces having open ends between the effectivesurfaces 47 b and 47 c. The focus leading surfaces 47 d and 47 e areinclined with respect to the circumferential direction in oppositedirections and at an equal inclination angle. The focus leading surfaces47 d and 47 e of the drive ring 47 and the driven projections 46 dformed on the rear sub-lens group frame 46 constitute a focus cammechanism.

[0062] The compression coil springs 51, which bias the front sub-lensgroup frame 45 rearwardly, cause the shift leading surfaces 45 c of thefront sub-lens group frame 45 to be always in contact with the followerprojections 46 a of the rear sub-lens group frame 46, and cause thedriven projections 46 d of the rear sub-lens group frame 46 to be alwaysin contact with the telephoto or wide-angle focus leading surfaces 47 dand 47 e. The drive ring 47 abuts at the rear end surface thereofagainst the receiving surface 42 s of the rear support ring 42, asmentioned above. The contact relationship of the front sub-lens groupframe 45, the rear sub-lens group frame 46, the drive ring 47, and therear support ring 42 (receiving surface 42 s) is maintained by thespring force of the compression coil springs 51. In contacting state, asshown in FIGS. 24 and 25, the front end of the rear sub-lens group frame46 is inserted inside the inner peripheral surface of the front sub-lensgroup frame 45, and the drive ring 47 is fitted on the outer peripheralsurface of the rear sub-lens group frame 46.

[0063] At the mutually distant position at the wide-angle side of thefirst sub-lens group S1 and the second sub-lens group S2, the effectivesurfaces 47 b of the drive ring 47 abut against the driven projections46 d, and the linear guide projections 46 c are disengaged from thewide-angle linear guide grooves 41 e. In this state, if the drive ring47 is moved in the right hand direction with respect to FIG. 22 (rotatedin the clockwise direction), the effective surfaces 47 b press againstthe driven projections 46 d and rotate the rear sub-lens group frame 46in the same direction, so that the linear guide projections 46 c abutagainst the rotation preventing surfaces 41 c. During this movement, thefront sub-lens group frame 45 (first sub-lens group S1) comes close tothe rear sub-lens group frame 46 (second sub-lens group S2) inaccordance with the engagement of the shift leading surfaces 45 c andthe follower projections 46 a of the rear sub-lens group frame 46 and,consequently, the follower projections 46 a are stably engaged in thefollower engaging recesses 45 e.

[0064] Thus, the switching from the mutually distant position at thewide-angle side to the mutually close position at the telephoto side iscompleted. Consequently, the first sub-lens group S1 is close to thesecond sub-lens group S2 (mutually close extremity, i.e., at a mutuallyclose position for a long focal length), and no further rotation of thedrive ring 47 in the same direction is permitted.

[0065] When the switching to the mutually close position at thetelephoto side is completed, the drive ring 47 is rotated in the reversedirection. Consequently, the driven projections 46 d (rear sub-lensgroup frame 46) are moved rearwardly in accordance with the telephotofocus leading surfaces 47 d and, hence, the linear guide projections 46c are engaged in the telephoto linear guide grooves 41 g, so that thelinear guide projections 46 c are linearly movable only in the axialdirection. The focusing operation on the telephoto side, from anintermediate focal length to the long focal length extremity (telephotoextremity), is carried out by the integral movement of the rear sub-lensgroup frame 46 and the front sub-lens group frame 45 at the mutuallyclose extremity via the telephoto focus leading surfaces 47 d. Namely,as shown in FIG. 23, when the drive ring 47 is rotated within thetelephoto focus area ft (from the infinite object distance 8 to theshortest object distance n) in a state that the driven projections 46 dof the rear sub-lens group frame 46 abut against the telephoto focusleading surfaces 47 d, the rear sub-lens group frame 46 whose rotationis restricted by the engagement of the telephoto linear guide grooves 41g, the linear guide projections 46 c, and the front sub-lens group frame45 whose rotation is restricted by the engagement of the linear guiderods 48 in the guide holes 45 b (i.e., the first sub-lens group S1 andthe second sub-lens group S2) are integrally moved together in theoptical axis direction to carry out the focusing operation.

[0066] When the drive ring 47 is rotated until the effective surfaces 47c come into contact with the driven projections 46 d, the linear guideprojections 46 c of the rear sub-lens group frame 46 are disengaged fromthe telephoto linear guide grooves 41 g. In this state, when the drivering 47 is moved in the left hand direction in FIG. 22 (rotated in thecounterclockwise direction), the effective surfaces 47 c press againstthe driven projections 46 d to thereby rotate the rear sub-lens groupframe 46 in the same direction. Consequently, the linear guideprojections 46 c abut against the rotation preventing surfaces 41 b.During this movement, the front sub-lens group frame 45 comes close tothe rear sub-lens group frame 46 in accordance with the engagement ofthe shift leading surfaces 45 c and the follower projections 46 a of therear sub-lens group frame 46, and the follower projections 46 a becomestably engaged in the follower engaging recesses 45 d. Thus, theswitching from the mutually close position at the telephoto side to themutually distant position at the wide-angle side is completed, so thatthe first sub-lens group S1 moves away from the second sub-lens group S2(mutually distant extremity, i.e., the mutually distant position for along focal length), and no further rotation of the drive ring 47 in thesame direction is permitted.

[0067] When the switching to the mutually distant position at thewide-angle side is completed, the drive ring 47 is rotated in thereverse direction. Consequently, the driven projections 46 d (rearsub-lens group frame 46) are moved rearwardly in accordance with thewide-angle linear guide grooves 41 e, and accordingly, the linear guideprojections 46 c are engaged in the wide-angle linear guide grooves 41 eand is linearly movable only in the optical axis direction. The focusingoperation on the wide-angle side, from an intermediate focal length tothe short focal length extremity, is carried out by the integralmovement of the rear sub-lens group frame 46 and the front sub-lensgroup frame 45 at the mutually distant extremity by the wide-anglelinear guide grooves 41 e. Namely, as shown in FIG. 23, when the drivering 47 is rotated within the wide-angle focus area fw (from theinfinite object distance 8 to the shortest object distance n) in a statethat the driven projections 46 d abut against the wide-angle focusleading surface 47 e, the rear sub-lens group frame 46 whose rotation isrestricted by the engagement of the wide-angle linear guide grooves 41 eand the linear guide projections 46 c, and the front sub-lens groupframe 45 whose rotation is restricted by the engagement of the linearguide rods 48 in the guide holes 45 b (i.e., the first sub-lens group S1and the second sub-lens group S2) are moved together in the optical axisdirection to carry out the focusing operation.

[0068] When the drive ring 47 is rotated until the effective surfaces 47b abut against the driven projections 46 d, the linear guide projections46 c of the rear sub-lens group frame 46 are disengaged from thewide-angle linear guide grooves 41 e and are returned to the initialstate.

[0069] As mentioned above, in the front unit 40A of the lens-shutterunit 40, the shifting operation for moving the first sub-lens group S1and the second sub-lens group S2 to the mutually distant position for ashort focal length, or to the mutually close position for a long focallength, and the focusing operation in which the first variable powerlens group L1 is entirely moved in the optical axis direction, can becarried out by controlling the rotation of the drive ring 47. Thefocusing operations on the telephoto side and the wide-angle side arecarried out by controlling the number of pulses counted by a pulser(encoder) of the driving system which drives the drive ring 47, withreference to the position (the position in which the direction of therotation of the drive ring 47 is reversed) in which the linear guideprojections 46 c of the rear sub-lens group frame 46 abut against therotation preventing surfaces 41 b or 41 c. For instance, the number ofthe pulses to move the focusing lens group (i.e., the first variablepower lens group L1 including the first sub-lens group S1 and the secondsub-lens group S2) to the shortest object distance n, the infiniteobject distance 8, or an object distance therebetween, from thereference position can be predetermined taking into account the leadangles of the telephoto and wide-angle focus leading surfaces 47 d and47 e. Therefore, focusing can be carried out based on the objectdistance data by controlling the number of pulses.

[0070] The drive ring 47 is provided, on the entire outer peripheralsurface of the rear end thereof, with a gear 47 f which is in mesh witha terminal gear 52 a (FIG. 18) of a reduction gear train 52, so that thegear 47 f can be rotated in the forward or reverse direction by areversible drive motor 53 rotating in the forward and reverse directions(see FIGS. 13 and 18).

[0071] A pinion 53 a of the reversible drive motor 53 is located on thefront side of the front support ring 41 and a gear 47 f of the drivering 47 is located between the front support ring 41 and the rearsupport ring 42, i.e., on the rear side of the front support ring 41.Consequently, the reduction gear train 52, shown in FIG. 13, whichtransmits the motor drive force from the pinion 53 a to the gear 47 f,is held between the front support ring 41 and the gear retainer ring 43in such a way that the gears are arranged along the outer peripheralsurface of the front support ring 41. Moreover, a rotating slit disc 54,which constitutes the pulser to detect the amount of rotation of thereversible drive motor 53, is provided in the vicinity of the pinion 53a of the reversible drive motor 53. A relay gear 55 is provided betweenthe rotating slit disc 54 and the pinion 53 a.

[0072] The reversible drive motor 53 is held in a motor holding recess41 h of the front support ring 41. The rotating slit disc 54 is held inthe slit disc holding recess 41 i of the front support ring 41 (shownbest in FIG. 17). The front support ring 41 is provided with aninterrupter holding recess 41 j communicatively connected to the slitdisc holding recess 41 i. A photo-interrupter 56 for detecting a driveamount of the reversible drive motor 53 for the switching operation ofthe sub-lens groups and for the focusing operation, is received in theinterrupter holding recess 41 j (see FIG. 17). The rotating slit disc 54is arranged in the photo-interrupter 56 (between two components of thephoto-interrupter), so that the rotation angle (amount of angulardisplacement) of the slit disc 54 can be detected by counting the numberof pulses. In other words, the drive amount of the reversible drivemotor 53 can be detected.

[0073] The rear unit 40B will be explained below. A lens shutter and adiaphragm mechanism are provided between the rear support ring 42 andthe sector retainer ring 44. As shown in FIGS. 13 and 14, the rearsupport ring 42 and the sector retainer ring 44 are provided with frontwall portions 42 a and 44 a in the form of circular discs extending inorthogonal planes, with respect to the optical axis, and three rear arms42 b and 44 b extending rearwardly in the optical axis direction fromthe front wall portions 42 a and 44 a, respectively. The lens shutterand the diaphragm mechanism are held between the front wall portions 42a and 44 a. The rear arms 42 b and 44 b are overlapped in the radialdirection of the lens barrel (see FIG. 15).

[0074] The lens shutter has three shutter sectors 60 and a shutter drivering 61 which opens and closes the shutter sectors 60. The diaphragmmechanism has three diaphragm sectors 62 and a diaphragm drive ring 63which opens and closes the diaphragm sectors 62. A separation plate 64is arranged between the shutter sectors 60 and the diaphragm sectors 62,and a separation plate 65 is arranged between the diaphragm sectors 62and the diaphragm drive ring 63. The separation plate 64 preventsinterference between the movable shutter sectors 60 and the movablediaphragm sectors 62, and the separation plate 65 prevents interferenceof the diaphragm sectors 62 with the rotatable shutter drive ring 61 andthe rotatable diaphragm drive ring 63. The sector retainer ring 44, theseparation plate 64 and the separation plate 65 are provided withphotographing circular openings 44 c, 64 a and 65 a, respectively, whichhave substantially in the same diameter about the optical axis O. Therear support ring 42 is provided with a center opening 42 c whosediameter is greater than the diameter of the photographing circularopenings 44 c, 64 a and 65 a.

[0075] The shutter sectors 60 and diaphragm sectors 62 which are eachmade of three blades are rotatably supported by projecting pivots(support pivots) 66 (only one of which is shown in FIGS. 13 and 14)which extend rearward from the front wall portions 42 a of the rearsupport ring 42. The projecting pivots 66 extend through support holes60 a and 62 a formed in the shutter sectors 60 and the diaphragm sectors62. Projecting pivot securing holes 44 d (see FIG. 14), in which thefront ends of the projecting pivots 66 are received, are formed in thefront wall portions 44 a of the sector retainer ring 44.

[0076] The shutter drive ring 61 is provided with three rotationtransmission dowels 61 a which are engaged in rotational guide cam slots60 b formed in the shutter sectors 60. The three shutter sectors 60 arerotated about the projecting pivots 66 in accordance with therelationship between the rotational guide cam slots 60 b and therotation transmission dowels 61 a when the shutter drive ring 61 isreciprocally rotated, so that the front portion of the photographingcircular opening 44 c is opened and closed. The aperture of the shuttersectors 60 can be controlled by the angular displacement of the shutterdrive ring 61. The sector retainer ring 44 is provided with dowelreceiving slots 44 e in which the front ends of the rotationtransmission dowels 61 a are inserted. The shutter drive ring 61 isbiased in the closing direction by a shutter drive ring biasing spring74, so that play (in the shutter drive ring 61) can be removed by theshutter drive ring biasing spring 74.

[0077] Similar to the shutter drive ring 61, the diaphragm drive ring 63is provided with three rotation transmission dowels 63 a which areengaged in rotational guide cam slots 62 b formed in the diaphragmsectors 62. The three diaphragm sectors 62 are rotated about theprojecting pivots 66 in accordance with the relationship between therotational guide cam slots 62 b and the rotation transmission dowels 63a when the diaphragm drive ring 63 is reciprocally rotated, so that thefront portion of the photographing circular opening 44 c is opened andclosed. The aperture of the diaphragm sectors 62 can be controlled bythe angular displacement of the diaphragm drive ring 63. The diaphragmsectors 62 are provided with through-holes 62 c to prevent interferencewith the rotation transmission dowels 61 a of the shutter drive ring 61regardless of the angular position of the diaphragm sectors 62. Thefront ends of the rotation transmission dowels 63 a are in contact with,and held by, the front surface of the front wall portion 44 a. Thediaphragm drive ring 63 is biased by a diaphragm drive ring biasingspring 72 which is engaged at one end thereof with the diaphragm drivering 63 and at the other end thereof with the rear support ring 42 in adirection to open the diaphragm sectors 62.

[0078] In the zoom lens barrel of the present invention, the shuttersectors 60 have a variable diaphragm function to determine a desiredaperture value and a shutter function, and are electrically controlledso that the amount of opening (aperture value) and the opening time(shutter speed) of the shutter sectors 60 are varied in accordance withthe exposure value when the shutter is released. The diaphragm sectors62 are provided to restrict the maximum value of the aperture at awide-angle object distance in particular, and the amount of openingthereof is varied in accordance with the feed amount of the zoom lensbarrel as a whole.

[0079] The shutter drive ring 61 for opening and closing the shuttersectors 60 is provided on the outer peripheral surface thereof with apartial sector gear 61 b which is in mesh with a reduction gear train 68connected to a shutter drive motor 67 (see FIGS. 13 and 18). The shutterdrive motor 67 is held in a motor holding recess 41 k (see FIG. 17) ofthe front support ring 41, and a pinion 67 a of the shutter drive motor67 is located in front of the front support ring 41. The reduction geartrain 68 transmits the drive force of the motor to the rear side of thefront support ring 41, and has a terminal gear 68 a distant from thepinion 67 a of the shutter drive motor 67 exposed to the rear portion ofthe front support ring 41 (front unit 40A), as shown in FIG. 18. Thefront wall portion 42 a of the rear support ring 42 is provided with athrough-hole 42 e in which the terminal gear 68 a of the reduction geartrain 68 is inserted so as to engage with the sector gear 61 b.

[0080] When the shutter drive motor 67 is rotated in the forward orreverse direction, the shutter drive ring 61 is rotated in the samedirection, so that the shutter sectors 60, which are in a closedposition, are instantaneously opened and closed. As mentioned above, theamount of opening, and the opening time of the shutter sectors 60 arevariable and are controlled in accordance with the drive signal(electric current) supplied to the shutter drive motor 67. Namely, ifthe rotation angle of the shutter drive ring 61 driven by the shutterdrive motor 67 is increased, the amount of opening of the shuttersectors 60 is increased and the aperture value is reduced (approaches afully open diaphragm position). If the rotation angle of the shutterdrive ring 61 is decreased, the amount of opening of the shutter sectors60 is decreased and the aperture value is increased (diaphragm closes).Moreover, if the time interval between the forward rotation and thereverse rotation of the shutter drive ring 61 driven by the shutterdrive motor 67 is shortened, the opening time of the shutter sectors 60is shortened, so that the shutter speed is increased. Conversely, if thetime interval between the forward rotation and the reverse rotation islengthened, the opening time of the shutter sectors 60 is prolonged,thus resulting in a slower shutter speed.

[0081] The shutter drive ring 61 has a slit plate 61 c which is in theform of a small portion of a cylinder and protrudes forward in theoptical axis direction. The slit plate 61 c extends through an arcopening 42 d (see FIG. 14), formed in the front wall portion 42 a of therear support ring 42, and an arc opening 41 m (see FIG. 17) formed inthe rear surface of the front support ring 41. The slit plate 61 c islocated in a photo-interrupter 69 (between two components of thephoto-interrupter 69) shown in FIG. 17, so that the passing of slits ofthe slit plate 61 c can be detected by the photo-interrupter 69 in orderto detect the shutter operation. Namely, the opening and closing of theshutter sectors 60 can be detected by the operation of the shutter drivering 61 via the slit plate 61 c and the photo-interrupter 69.

[0082] The front support ring 41 is provided with an interrupter holdingrecess 41 n (see FIG. 17) for receiving the photo-interrupter 69. Theinterrupter holding recess 41 n is located adjacent to the interrupterholding recess 41 j for receiving the photo-interrupter 56 for detectingthe switching and focusing drive amount. The recesses 41 n and 41 j arecovered by a common cover 70 in the form of a leaf spring. The twophoto-interrupters 56 and 69 are held by the leaf spring cover 70.

[0083] As can be understood from the foregoing, in the zoom lens barrelof the present embodiment, the exposure is controlled by the shuttersectors 60. The purpose of the diaphragm sectors 62 is to restrict thesize of the aperture so that the peripheral portion of the zoom lenssystem is not used for photographing at the short focal length.

[0084] The diaphragm drive ring 63, for opening and closing thediaphragm sectors 62, is provided on the outer peripheral surfacethereof with a driven projection 63 b which is engaged in a diaphragmcontrol cam groove 71 (see FIG. 10) formed in the inner peripheralsurface of the arm 33 b of the third linear guide ring 33. Upon zooming,the third linear guide ring 33 and the lens-shutter unit 40 (diaphragmdrive ring 63) are relatively moved in the optical axis direction.Consequently, the driven projection 63 b is moved in the circumferentialdirection in accordance with the diaphragm control cam groove 71 torotate the diaphragm drive ring 63 to thereby vary the opening degree ofthe diaphragm sectors 62. As shown in FIG. 11, the diaphragm control camgroove 71 includes a linear restriction portion 71 a extending parallelwith the optical axis O, an oblique restriction portion 71 b which isinclined with respect to the optical axis O, and a restriction releasingportion 71 c which opens into the front end of the third linear guidering 33. The width of the linear restriction portion 71 a and theoblique restriction portion 71 b is such that the driven projection 63 bcan be substantially snugly fitted therein.

[0085] When the zoom lens barrel is in the retracted position(accommodated position) shown in FIG. 2, the driven projection 63 b islocated in the linear restriction portion 71 a. When the zoom lensbarrel is advanced to the wide-angle position, the driven projection 63b is still in the linear restriction portion 71 a. When the drivenprojection 63 b is in the linear restriction portion 71 a, the drivenprojection 63 b causes the aperture defined by the three diaphragmsectors 62 to be at a minimum aperture position. In the minimum apertureposition, the diaphragm sectors 62 do not completely close the frontportion of the photographing circular opening 44 c but cover apredetermined width of the peripheral portion of the circular opening inthe radial direction. Consequently, photographing is carried out at thewide-angle extremity without collecting unnecessary light.

[0086] When the zoom lens barrel is advanced toward the telephoto sideand reaches the fourth focal length step from the wide-angle extremity,the driven projection 63 b enters the oblique restriction portion 71 bfrom the linear restriction portion 71 a. The oblique restrictionportion 71 b is inclined so that the diaphragm drive ring 63 is rotatedin the diaphragm opening direction as the driven projection 63 b ismoved toward the restriction releasing portion 71 c. Therefore, when thelens barrel is advanced while the driven projection 63 in located in theoblique restriction portion 71 b, the diaphragm drive ring 63 is rotatedin the diaphragm opening direction to gradually open the diaphragmsectors 62. Specifically, a middle opening degree of the diaphragmsectors 62 is obtained at the fifth focal length step counting from thewide-angle extremity, and the diaphragm sectors 62 are fully opened atthe sixth focal length step.

[0087] When further advancement of the zoom lens barrel takes place, theabove-mentioned switching of the relative distance between the firstsub-lens group S1 and the second sub-lens group S2 is carried betweenthe sixth focal length step and the seventh focal length step, so thatwide-angle photographing mode is transferred to the telephotophotographing mode. In the telephoto photographing mode, the drivenprojection 63 b is located in the restriction releasing portion 71 c.The restriction releasing portion 71 c is shaped so as to give lessrestriction on the relative position of the driven projection 63 b. Whenthe driven projection 63 b is in the restriction releasing portion 71 c,the diaphragm drive ring 63 is held at an angle position to open thediaphragm sectors 62 by the diaphragm drive ring biasing spring 72.Therefore, in the telephoto photographing mode, a sufficient amount oflight can be collected.

[0088] Conversely, when the zoom lens barrel is moved toward thewide-angle side from the telephoto side, the opening degree of thediaphragm sectors 62 is gradually reduced from the fifth focal lengthstep counting from the wide-angle extremity. The diaphragm sectors 62are closed in accordance with the relationship between the linearrestriction portion 71 a and the driven projection 63 b, from the fourthfocal length step to the wide-angle extremity (first focal length step).Note that the restriction releasing portion 71 c has an inclined guidesurface 71 d which is adapted to smoothly guide the driven projection 63b to the oblique restriction portion 71 b when the photographing mode istransferred from the telephoto photographing mode to the wide-anglephotographing mode. The inclined guide surface 71 d ensures that thedriven projection 63 b is moved into the oblique restriction portion 71b without interfering with the diaphragm control cam groove 71, even ifthe angular position of the diaphragm drive ring 63 which has beenreleased at the telephoto photographing mode is slightly out ofalignment.

[0089] In the rear unit 40B constructed as above, the rotatable shutterdrive ring 61 and the rotatable diaphragm drive ring 63 are locatedsubstantially in the same position in the axial direction. The shutterdrive ring 61 is supported on the inner diameter side of the diaphragmdrive ring 63 (see FIG. 15). The diaphragm drive ring 63 is provided onthe inner peripheral surface thereof with three inner diameter thrustprojections 63 c that are spaced in the circumferential direction atequi-angular intervals to rotatably support the shutter drive ring 61.The shutter drive ring 61 is provided on the outer peripheral surfacethereof with three outer diameter thrust projections 61 d that arespaced in the circumferential direction at equi-angular intervals toengage with the inner diameter thrust projections 63 c. The diaphragmdrive ring 63 is in contact with the rear surface of the front wallportion 42 a of the rear support ring 42 and the rotation transmissiondowels 63 a are in contact with the front surface of the front wallportion 44 a of the sector retainer ring 44, so that the diaphragm drivering 63 is supported between the rear support ring 42 and the sectorretainer ring 44 so as not relatively move in the optical axisdirection. The driven projection 63 b of the diaphragm drive ring 63supported between the rear support ring 42 and the sector retainer ring44 (between the front wall portion 42 a and the front wall portion 44 a)is located between a pair of rear arms 42 b and 44 b in thecircumferential direction, so that the driven projection 63 b can beengaged by the diaphragm control cam groove 71 of the third linear guidering 33 (see FIG. 10). The shutter drive ring 61 is supported betweenthe rear support ring 42 and the sector retainer ring 44, with theshutter drive ring 61 in contact with the rear surface of the front wallportion 42 a and with the outer diameter thrust projections 61 d beingengaged with the inner diameter thrust projections 63 c. The diaphragmdrive ring 63 is shaped so that the sector gear 61 b (see FIGS. 24 and25) of the shutter drive ring 61, located inside the diaphragm drivering 63, can engage with the reduction gear train 68.

[0090] As can be understood from the above discussion, the lens-shutterunit 40 includes the front unit 40A having the first variable power lensgroup L1 (first sub-lens group S1 and second sub-lens group S2) and thedrive mechanism therefore, and the rear unit 40B having the lens shutterand the diaphragm mechanism. The front unit 40A includes the reversibledrive motor 53 for driving the first variable power lens group L1, andthe shutter drive motor 67 for opening and closing the shutter sectors60. The front unit 40A is also provided with the photo-interrupter 56which detects the shift movement of the first sub-lens group S1 and thesecond sub-lens group S2 and the movement of the entire first variablepower lens group L1 during the focusing operation, and thephoto-interrupter 69 which detects the opening and closing operation ofthe shutter sectors 60. The reversible drive motor 53, the shutter drivemotor 67, and the photo-interrupters 56 and 69 are connected to acontrol circuit 81 (see FIG. 2) in the camera body 11 via a lens-shutterunit FPC (flexible printed circuit) 80. As shown in FIGS. 13 and 16, thelens-shutter unit FPC 80 is divided into an annular FPC 80A extendingaround the outer peripheral surface of the front unit 40A, and afoldable strip FPC 80B which is elongated in the optical axis direction.The annular FPC 80A is double-sided FPC having circuit patterns printedon upper and lower surfaces thereof. The foldable strip FPC 80B is aone-sided FPC having a circuit pattern printed on only one of upper andlower surfaces thereof.

[0091] The foldable strip FPC 80B is secured at a shutter securing end80B-1 to the front support ring 41 by a securing screw 82, as shown inFIG. 13. An FPC support plate 83 is inserted between the shuttersecuring end 80B-1 and the securing screw 82. A cylindricalpress-contact support rubber 84 is inserted between the shutter securingend 80B-1 and the front support ring 41. As shown in FIGS. 2 and 4, thefoldable strip FPC 80B is connected at the other end to the controlcircuit 81. The foldable strip FPC 80B can be freely deformed to varythe position of the bent portions and the linear portions thereof inaccordance with the relative position of the lens-shutter unit 40 andthe control circuit 81 which is changed in accordance with the advanceor retraction of the zoom lens barrel, to prevent an interference of theFPC with other members of the lens barrel or the photographing lightpath. The foldable strip FPC 80B is not connected to the motors(reversible drive motor 53 and the shutter drive motor 67) or thephoto-interrupters 56 and 69 when the foldable strip FPC 80B is solelymounted to the front support ring 41. Namely, the motors and thephoto-interrupters are connected to the control circuit 81 when theannular FPC 80A is mounted.

[0092] As shown in FIG. 17, the annular FPC 80A has two motor terminals80A-1 and 80A-2 to supply power to the reversible drive motor 53 and theshutter drive motor 67, and two interrupter terminals 80A-3 and 80A-4 toreceive the pulses output from the photo-interrupters 56 and 69,respectively. The wiring conductors extending from the terminals aregathered at a press-contact portion 80A-5. The press-contact portion80A-5 is brought into press contact with the shutter securing end 80B-1of the foldable strip FPC 80B, so that the wiring conductors of theannular FPC 80A and the foldable strip FPC 80B are connected. Thus, thereversible drive motor 53, the shutter drive motor 67, and thephoto-interrupters 56 and 69 are electrically connected to the controlcircuit 81. The press-contact portion 80A-5 of the annular FPC 80A isfastened together with the shutter securing end 80B-1 of the foldablestrip FPC 80B by the securing screw 82, and are secured to the frontsupport ring 41. The annular FPC 80A is also provided with fourpositioning holes 80A-6 in which front surface projections 43 c (seeFIGS. 20 and 21) of the gear retainer ring 43 are fitted to determinethe position thereof.

[0093] The leaf spring cover 70, which holds the photo-interrupters 56and 69, covers the portion of the annular FPC 80A hatched in FIG. 17 tostably hold the annular FPC 80A.

[0094] As shown in FIG. 26, the control circuit 81 controls the zoomingmotor 15 as well as the reversible motor 53 and the shutter drive motor67. Focal length information 81A set by an operator (photographer) via azoom switch (zoom operating device) etc., detected object distanceinformation 81B, object brightness information 81C, angular positioninformation of the cam ring 30 detected by a focal length detectiondevice including the brush 19 and the code plate 20, focusing driveamount information (position switching information of the first sub-lensgroup S1 and the second sub-lens group S2) detected by thephoto-interrupter 56, and opening and closing state information of theshutter sectors 60 detected by the photo-interrupter 69 are input to thecontrol circuit 81. The zooming motor 15, the reversible drive motor 53,and the shutter drive motor 67 are controlled so that the exposure iscarried out under the correct exposure conditions at the set focallength, based on the input information. Note that although, in theillustrated embodiment, the shutter sectors 60 function as a shutter anda variable diaphragm, and the diaphragm sectors 62 restrict the aperturesize at the wide-angle photographing position, it is possible to use avariable diaphragm mechanism in which the diaphragm sectors 62 areelectrically driven by a motor.

[0095] The lens-shutter unit 40 is assembled with the members discussedabove into a unit which is incorporated in the lens support barrel 31.Namely, the front unit 40A and the rear nit 40B are assembledseparately, the two units 40A and 40B are secured using three unitsecuring screws 39 (see FIG. 13), and the assembly of the units 40A and40B is mounted into the lens support barrel 31.

[0096] As shown in FIG. 21, the rear support ring 42 of the lens-shutterunit 40 is provided with engagement projections 42 f provided on theouter surfaces of the three rear arms 42 b. The engagement projections42 f are engaged in the engagement holes 31 c of the lens support barrel31. The engagement projections 42 f are formed on resilient tongueportions 42 g which are elastically deformable in the radial directions.When the lens-shutter unit 40 is inserted in the direction indicated byan arrow in FIG. 21 into the lens support barrel 31, the engagementprojections 42 f are moved inwardly by the inner surface of the lenssupport barrel 31, so that the elastic tongue portions 42 g areelastically deformed inwardly. Further insertion o the lens-shutter unit40 causes the engagement projections 42 f to engage in the engagementholes 31 c, so that the elastic tongue portions 42 g are returned to theinitial state, or the inward deformation of the elastic tongue portions42 g is reduced. The cross sectional shape of the engagement projections42 f is such that the elastic tongue portions 42 g can be easilydeformed inwardly when the lens-shutter unit 40 is inserted forwardly inthe optical axis direction, and the lens-shutter unit 40 cannot slip offthe lens support barrel 31 in the rearward direction. Therefore, whenthe engagement projections 42 f engage in the engagement holes 31 c, thelens-shutter unit 40 is held in the lens support barrel 31. Threelens-shutter unit retainer springs 73 (see FIGS. 1 and 13) are providedbetween the lens-shutter unit 40 and the lens support barrel 31 to biasthe lens-shutter unit 40 rearwardly in the optical axis direction.Accordingly, the axial position of the lens-shutter unit 40 can beaccurately determined.

[0097] It is possible to adjust the position of the lens-shutter unit 40in a direction perpendicular to the optical axis, during the assembly ofthe lens barrel. The lens support barrel 31 is provided on the innerperipheral surface thereof with a substantially annular front wallportion 31 b in the vicinity of the front end of the lens support barrel31. The front wall portion 31 b is provided with an insertion hole 31 e(see FIG. 21) in which an eccentric member 85 and a direction member 86are rotatably fitted. The eccentric member 85 is engaged in the gearretainer ring 43 of the lens-shutter unit 40. The eccentric member 85and the direction member 86 are relatively rotatable. When the directionmember 86 is rotated from the front end of the lens support barrel 31,the front end of the eccentric member 85 (the end of the eccentricmember engaging with the lens-shutter unit 40) is moved in a planeperpendicular to the optical axis O. Consequently, the position of thelens-shutter unit 40 in the direction perpendicular to the optical axiswithin the lens support barrel 31 is varied, whereby the position of thefirst variable power lens group L1 supported by the lens-shutter unitcan be adjusted.

[0098] The lens support barrel 31 is provided on the front end thereofwith a lens barrier mechanism which opens and closes the front openingof the first variable power lens group L1. As shown in FIG. 1, the lensbarrier mechanism has a barrier unit including an outer decorative plate90 secured to the front end of the lens support barrel 31, a barrierretainer ring 96, a pair of outer barrier blades 92 and a pair of innerbarrier blades 93 which are rotatably mounted between the barrierretainer ring 96 and the decorative plate 90, and barrier springs 94. Abarrier drive ring 91 is supported between the barrier unit and thefront end 31 b of the lens support barrel 31 so as to be rotatable aboutthe optical axis O. The decorative plate 90 is provided with aprojection (not shown) which rotatably supports the outer and innerbarrier blades 92 and 93. The outer and inner barrier blades 92 and 93are rotated about this projection and are associated with each other tocarry out the opening and closing operation. The barrier blades 92 and93 are biased by the barrier springs 94 in a closing direction.

[0099] The barrier drive ring 91 is provided with diametrically opposedbarrier engagement portions 91 a and a driven arm 91 b which extendsrearwardly in the optical axis direction. The barrier engagementportions 91 a engage with the inner barrier blades 93 to transmit therotation of the barrier drive ring 91 to the inner barrier blades 93.The inner barrier blades 93 are associated with the outer barrier blades92, and hence, the rotation of the barrier drive ring 91 is transmittedto the outer barrier blades 92 via the inner barrier blades 93. Thedriven arm 91 b extends through a center opening 31 d of the front wallportion 31 b (see FIG. 21) into the lens support barrel 31. The drivenarm 91 b can be engaged with an inclined guide surface 33 e formed onthe front end of the partially cylindrical arm 33 b of the third linearguide ring 33.

[0100] The barrier drive ring 91 is biased by the drive ring biasingspring 95 in a direction to open the barrier blades 92 and 93. The drivering biasing spring 95 is stronger than the barrier biasing spring 94,so that the biasing force of the drive ring biasing spring 95 istransmitted to the barrier blades 92 and 93 through the barrierengagement projections 91 a to thereby open the barrier blades 92 and 93against the barrier spring 94 when the barrier drive ring 91 is in afree state. At the wide-angle extremity shown in FIG. 3 and at thetelephoto extremity shown in FIG. 4, the driven arm 91 b and theinclined guide surface 33 e do not come into contact with each other, sothat the barrier drive ring 91 is free and, hence, the barrier blades 92and 93 are open (see FIG. 25). When the zoom lens barrel is moved fromthe wide-angle extremity to the retracted position shown in FIG. 2, theinclined guide surface 33 e of the third linear guide ring 33 engageswith the driven arm 91 b of the barrier drive ring 91, so that thebarrier drive ring 91 is forcedly rotated in a direction against thedrive ring biasing spring 95, i.e., in a direction to permit the barrierblades 92 and 93 to be closed, in accordance with the shape of theinclined guide surface 33 e. Consequently, the barrier blades 92 and 93which have been released from the restriction by the barrier drive ring91 are closed by the spring force of the barrier spring 94 (see FIG.24).

[0101] As mentioned above, in the zoom lens barrel of the presentembodiment, the drive ring 47 is rotated to move the first variablepower lens group L1 in the optical axis direction to carry out thefocusing operation. As indicated by two-dotted chain line in FIG. 25,when the first variable power lens group L1 is moved to the frontextremity of the movement for the focusing operation, the front end ofthe front sub-lens group frame 45 which supports the first sub-lensgroup S1 is moved to a position located more forward than the axialpositions of the barrier blades 92 and 93. Note that FIG. 25 shows thetelephoto photographing mode in which the first sub-lens group S1 andthe second sub-lens group S2 are in the mutually close position.Likewise, at the wide-angle photographing mode in which the firstsub-lens group S1 and the second sub-lens group S2 are in the mutuallydistant position, the front end of the front sub-lens group frame 45 ismoved to a position located more forward than the axial positions of thebarrier blades 92 and 93 at the front extremity of the movement for thefocusing operation.

[0102] As mentioned above, the lens support barrel (outer lens barrel)31 is provided on the front end thereof with the lens barrier mechanism,which opens and closes the opening in front of the first variable powerlens group L1, and includes the outer decorative plate 90, the barrierdrive ring 91, the outer barrier blades 92, the inner barrier blades 93,the barrier springs 94, and the drive ring biasing spring 95. In theretracted position of the lens barrel (non-use position) shown in FIG.2, the barrier blades 92 and 93 close the center opening (photographingaperture) 31 d (see FIGS. 21 and 24) of the front wall portion 31 bprovided in the vicinity of the front end of the lens support barrel 31due to the biasing force of the barrier spring 94 (see FIG. 1). Namely,the front portion of the first variable power lens group L1 is closed inthe retracted position, as shown in FIG. 24. When the lens barrel isadvanced to the wide-angle extremity position shown in FIG. 3, theinclined guide surface 33 e (see FIG. 9) of the third linear guide ring33 is disengaged from the driven arm portion 91 b of the barrier drivering 91, so that the barrier drive ring 91 is rotated to open thebarrier by the drive ring biasing spring 95. Consequently, when the lensbarrel is advanced at least to the wide-angle extremity position, thebarrier blades 92 and 93 open the photographing aperture (center opening31 d) in front of the first variable power lens group L1, as shown inFIG. 25. In an intermediate photographing position between thewide-angle extremity position shown in FIG. 3 and the telephotoextremity position shown in FIG. 4, the inclined guide surface 33 e ofthe third linear guide ring 33 is always disengaged from the driven arm91 b of the barrier drive ring 91, and hence, the barrier blades 92 and93 are maintained in an open state.

[0103] One of the significant features of the zoom lens barrel residesin that the opening state of the barrier blades 92 and 93 is detected bythe movement of the first variable power lens group L1. Among thevariable power lens groups L1 and L2 which constitute the zoom lenssystem, the first variable power lens group L1 is a focusing lens groupwhich is moved in the optical axis direction by the reversible drivemotor 53, independently of the zooming operation. The focusing operationto integrally move the first and second sub-lens groups S1 and S2, whichconstitute the first variable power lens group L1, together in theoptical axis direction has been discussed above. When the first variablepower lens group L1 is moved to the forward movement extremity withinthe movement range thereof, the front end of the front sub-lens groupframe (lens support frame/front lens support frame) 45 which supportsthe first sub-lens group S1 is moved to the position in front of thebarrier blades 92 and 93 in the optical axis direction (see FIG. 25).The front end of the front sub-lens group frame 45 is held in a positionbehind the barrier blades 92 and 93 in the optical axis direction whenthe first variable power lens group L1 is moved to the rearward movementextremity via the drive ring (lens drive mechanism/focus drivemechanism/sub-lens group shifting device) 47 (see FIG. 24).

[0104] As can be seen in FIG. 25, the position of the outer peripheralsurface 45 f of the front sub-lens group frame 45 in the radialdirection about the optical axis C is slightly inward with respect tothe barrier inner diameter portions 92 a and 93 a of the barrier blades92 and 93 in an open position. Therefore, when the barrier blades 92 and93 are slightly closed with respect to the open position shown in FIG.25, if the first variable power lens group L1 is moved to the forwardmovement extremity (indicated by two-dotted and dashed line in FIG. 25)within the movement range for the focusing operation, the front end ofthe front sub-lens group frame 45 is brought into contact with the outerbarrier blade 92 or the inner barrier blade 93 during the movement.Consequently, the front sub-lens group frame 45 and rear sub-lens groupframe (lens support frame/rear lens support frame) 46 interfere with thebarrier blade 92 or 93, so that further forward movement thereof isprevented. The driving amount of the reversible drive motor 53 whichmoves the sub-lens group frames 45 and 46 is detected as pulses via therotating slit disc 54 and the photo-interrupter 56. If the movement ofthe sub-lens group frames 45 and 46 is prevented, the pulse count isalso stopped (i.e., no increase of the number of pulses occurs).Consequently, it is possible to detect whether or not the first variablepower lens group L1 is moved to the forward movement extremity, withreference to the movement of the first variable power lens group L1(sub-lens group frames 45, 46) which is obtained as the number of pulsesvia the slit disc 54 and the photo-interrupter 56. If the barrier blades92 and 93 interfere with the front sub-lens group frame 45, the firstvariable power lens group L1 is not correctly moved to the forwardmovement extremity, so that an error is detected by the control circuit(barrier detection device/control device) 81 accordingly.

[0105] In the camera of this embodiment, the opening state of thebarrier can be detected based on the concept mentioned above. Namely,the control is carried out as shown in FIG. 27. The control circuit 81drives the reversible drive motor 53 prior to the photographingoperation to thereby move the first variable power lens group L1 towardthe forward movement extremity indicated by two-dotted and dashed linein FIG. 25 from the rearward movement extremity (Step 1 in FIG. 27). Thelens driving operation is carried out not for the focusing operation butfor a scanning operation to check the opening and closing state of thebarrier blades. The time counting operation begins at the same time asthe commencement of the scanning operation (Step 2). The number of drivepulses of the reversible drive motor 53 necessary to move the firstvariable power lens group L1 to the forward movement extremity ispre-stored. When the pre-stored number of drive pulses is detectedwithin a predetermined time (Step 3, YES), it can be confirmed that thefirst variable power lens group L1 has been moved to the forwardmovement extremity. Namely, it can be judged that there is nointerference of the barrier blades 92 and 93 with the front sub-lensgroup frame 45. Thereafter, the control circuit 81 stops the reversibledrive motor 53 (Step 4).

[0106] Conversely, if the pre-stored number of drive pulses is notdetected within a predetermined time (Step 3, NO), it can be judged thatthe forward movement of the first variable power lens group L1 has beenprevented due to some reason, for example, an interference of thebarrier blades 92 and 93 with the front sub-lens group frame 45.Consequently, the control circuit 81 stops the reversible drive motor 53(Step 5), and at the same time, the control circuit 81 causes a finderindicator (indication/warning device) 99 within the finder opticalsystem provided separately from the photographing optical system toindicate that the photographing operation cannot be performed (Step 6).A photographer can recognize the failure of operation via the finderindicator 99, and hence, there is no or little chance of a picture beingtaken while the barrier blades 92 and 93 are not completely opened. Theerror indication does not necessary have to be indicated within thefinder like in the case of the finder indicator 99, error indication canbe display in, e.g., an external display of the camera providedseparately from the finder.

[0107] Alternatively, the control circuit 81 may carry out an operationother than, and/or in addition to, indication/warning, in response tothe error detected by the scanning operation by the first variable powerlens group L1. For example, when the error occurs, the control circuit81 can prohibit receiving the shutter release signal, so that if theshutter release signal is issued, no movement of the shutter sectors 60takes place (i.e., no exposure occurs).

[0108] Note that the first variable power lens group L1 is returned tothe initial position (rearward movement extremity) by reversing thereversible drive motor 53 after the completion of the scanningoperation, regardless of whether an error occurs (Step 7). Thereafter,control enters into a stand-by mode.

[0109] The timing at which the detection of the barrier opening state iscarried out using the first variable power lens group L1 is optional.For instance, in the camera of the illustrated embodiment, the lensbarrel is moved from the retracted position shown in FIG. 2 to thewide-angle side photographing position shown in FIG. 3 when a mainswitch 98 (see FIG. 26) is turned ON. It is desirable for the firstvariable power lens group L1 be moved from the rearward movementextremity toward the forward movement extremity and that the barrieropening state be checked when the forward movement of the lens barrel tothe wide-angle extremity is completed after the main switch 98 is turnedON. This is because since the opening and closing operations of thebarrier blades 92 and 93 are carried out between the retracted positionof the lens barrel and the wide-angle extremity position, it can beassumed that if the barrier blades 92 and 93 are correctly opened at thewide-angle extremity position, there is no failure of the opening andclosing operation of the barrier blades 92 and 93. However, it isalternatively possible to check the opening and closing of the barrierat another time by moving the first variable power lens group L1.

[0110] As mentioned above, the first variable power lens group L1 alsohas a function to vary the distance between the first sub-lens group S1and the second sub-lens group S2. It is possible to utilize the movementof the sub-lens groups to come close to (the mutually close position) oraway from (the mutually distant position) each other in order to checkthe opening state of the barrier blades 92 and 93, in place of thefocusing operation. Namely, as shown in FIGS. 2 through 4, as the axialposition of the rear sub-lens group frame 46 within the lens-shutterunit is not varied by any operations other than the focusing operation,the movement of the sub-lens groups S1 and S2 to the mutually close anddistant positions substantially corresponds to the forward or rearwardmovement of the front sub-lens group frame 45 relative to the rearsub-lens group frame 46. As shown in FIG. 2, when the lens barrel islocated in the retracted position, the front sub-lens group frame 45 isin a mutually close position (mutually close position on the telephotoside discussed in connection with the whole structure of the lensbarrel) in which the front sub-lens group frame 45 is close to the rearsub-lens group frame 46. In this position, the front end of the frontsub-lens group frame 45 is located behind the barrier blades 92 and 93in the optical axis direction. When the lens barrel is used and moved tothe wide-angle extremity, the first sub-lens group S1 and the secondsub-lens group S2 are at a mutually distant position (mutually distantposition for wide-angle side). The switching operation of the mutuallyclose position to the mutually distant position corresponds to themovement of the front sub-lens group frame 45 to the forward movementextremity (distant position) relative to the rear sub-lens group frame46 which is not moved in the optical axis direction. Therefore, if theposition of the front end of the front sub-lens group frame 45 at theforward movement extremity thereof is set to be behind the barrier lades92 and 93 in the optical axis direction, the barrier opening state canbe detected by the distance varying movement of the sub-lens groups S1and S2, similar to the previous embodiment in which the detection of thebarrier opening state is carried out by the scanning operation using thefocusing operation.

[0111] Namely, the reversible drive motor 53 moves the first sub-lensgroup S1 and the second sub-lens group S2 from the mutually closeposition (rearward movement extremity of the front sub-lens group frame45) toward the mutually distant position (forward movement extremity ofthe front sub-lens group frame 45) while the main switch 98 is turned ONto move the lens barrel from the retracted position to the wide-angleextremity. During the movement of the first and second sub-lens groupsS1 and S2 to the mutually distant position, if the front sub-lens groupframe 45 is in contact with the barrier blade 92 or 93, so that themovement thereof is restricted, the number of the pulses correspondingto the stored number of pulses is not counted within a predeterminedtime, hence error is detected by the control circuit 81, similar to theprevious embodiment in which the detection is carried out by thescanning operation using the focusing operation. The operationssubsequent to the detection of the error are the same as those in theprevious embodiment. Note that since the movement of the first sub-lensgroup S1 and the second sub-lens group S2 to vary the distancetherebetween is carried out by the reversible drive motor 53,independent from the zooming motor 15 which moves the whole lens barrel,it is possible to feed the whole lens barrel to a photographableposition (wide-angle extremity), even if the error in the movement ofthe front sub-lens group frame 45 is detected.

[0112] As can be understood from the foregoing, in the camera to whichthe present invention is applied, the function of the photographing lenssupport frame (front sub-lens group frame 45) which is movable in theoptical axis direction is utilized, so that the opening state of thelens barrier is detected based on the movement of the photographing lenssupport frame to the forward movement extremity. Thus, it is notnecessary to provide an additional element (sensor) which only functionsto detect the barrier opening state. Consequently, the number of thecomponents can be reduced while ensuring reliable detection of thebarrier opening state, and therefore a compact and inexpensive cameracan be achieved. Namely, according to the present invention, a compactand inexpensive camera in which the opening state of the lens barriercan be reliably detected can be provided.

[0113] The present invention is not limited to the illustratedembodiments. For instance, although the photographing lens group (firstvariable power lens group L1) provided immediately behind the lensbarrier is composed of two sub-lens groups which are moved close to andaway from one another in the illustrated embodiments, it isalternatively possible to provide a focusing lens group having lenselements which are integral so as to always move together withoutvarying the distance therebetween. In this alternative, the supportframe of the focusing lens group can be moved in the optical axisdirection by a feed screw or a helicoid mechanism instead of the facecam in the illustrated embodiment.

[0114] Although the above discussion has been addressed to a zoom lenscamera, the present invention can be applied to a single focus lenscamera. In this application, the lens support frame 31 in theillustrated embodiments can be replaced with an outer barrel of a singlefocus lens barrel.

[0115] In short, the present invention can be equally applied to acamera having a lens barrier and a lens support frame (lens group)located immediately thereafter, which is movable in the optical axisdirection.

[0116] Furthermore, obvious changes may be made in the specificembodiment of the present invention described herein, such modificationsbeing within the spirit and scope of the invention claimed. It isindicated that all matter contained herein is illustrative and does notlimit the scope of the present invention.

What is claimed is:
 1. A camera comprising: a lens support frame whichsupports a photographing lens group; an outer lens barrel which isprovided on the front end thereof with a photographing aperture throughwhich said lens support frame is moved; a lens barrier mechanism whichopens and closes said photographing aperture of said outer lens barrel;a lens drive mechanism which moves said lens support frame in said outerlens barrel between a forward movement extremity in which the front endof said lens support frame is located in front of said photographingopening in an optical axis direction, and a rearward movement extremityin which the front end of said lens support frame is located behind saidphotographing aperture; and a barrier detection device for detecting theopening state of said lens barrier mechanism, based on an amountmovement of said lens support frame in the optical axis direction viasaid lens drive mechanism.
 2. The camera according to claim 1, whereinsaid barrier detection device detects the opening state of said lensbarrier mechanism based on an amount of forward movement of said lenssupport frame from the rearward movement extremity.
 3. The cameraaccording to claim 1, wherein said photographing lens group comprises afocusing lens group; wherein said lens drive mechanism comprises a focusdrive mechanism which moves said lens support frame to an in-focusposition of said focusing lens group, based on an object distance; andwherein said barrier detection device causes said focus drive mechanismto move said lens support frame, independently of a focusing operation,to detect the opening state of said lens barrier, based on the amount ofmovement of said lens support frame.
 4. The camera according to claim 1,wherein said photographing lens group is comprised of front and rearsub-lens groups; wherein said lens support frame is comprised of frontand rear lens support frames which support said front and rear sub-lensgroups, respectively; wherein said lens drive mechanism comprises asub-lens group shifting device which moves said front lens support framebetween a mutually close position in which said front lens support frameis close to said rear lens support frame, and a mutually distantposition in which said front lens support frame is distant from saidrear lens support frame; and wherein said front lens support frame issupported in said mutually close position when the camera is not used,and said front lens support frame is moved from said mutually closeposition to said mutually distant position by said sub-lens groupshifting device when the camera is used, so that said barrier detectiondevice detects the opening state of said lens barrier based on theamount of movement of said front lens support frame.
 5. The cameraaccording to claim 4, wherein said camera comprises a zoom lens camera;and wherein said sub-lens group shifting device moves said front lenssupport frame between said mutually close position and said mutuallydistant position with respect to said rear lens support frame, inaccordance with the movement of said zoom lens between a telephoto sidephotographing position and a wide-angle side photographing position. 6.The camera according to claim 4, further comprising a focus drivemechanism which moves said front lens support frame together with saidrear lens support frame to an in-focus position in the optical axisdirection, in accordance with an object distance; wherein said barrierdetection device causes said focus drive mechanism to integrally movesaid front and rear lens support frames together in the optical axisdirection, independently of a focusing operation, to detect the openingstate of said lens barrier in accordance with the amount of movement ofsaid front end rear lens support frames.
 7. The camera according toclaim 1, further comprising an indication device for indicatinginterference of said lens support frame with said lens barrier, detectedby said barrier opening state detection device.
 8. The camera accordingto claim 1, further comprising a control device for prohibiting aphotographing operation when interference of said lens support framewith said lens barrier is detected by said barrier detection device.